The goal of the proposed research is to develop novel methods for the detection of protein-protein interactions involving phosphoproteins and for intra and intermolecular distance measurements in various assemblies involving phosphoproteins - BioTraces' proprietary Multi Photon DetectionTM (MPDTM) system will be modified for the measurement of b-particle stimulated fluorescence (BSF) and the coincident detection of Cerenkov radiation excitation of fluorescence (CREF). The methods promise to provide a high sensitivity alternative to conventional fluorescence resonance energy transfer (FRET) techniques for monitoring the proximity of labeled biomoIecules. The methods will be tested on several model DNA and oligopeptide systems with the ultimate goal of applying them in studies of various CaM kinase II mediated phosphorylation cascades that are important for neuronal function. PROPOSED COMMERCIAL APPLICATIONS: The ability to characterize interactions among biomolecules and, in particular those involving phosphoproteins, is of immense importance to studies of the molecular basis of a variety of cellular functions, including various neuronal functions. Development of the methods proposed here will provide a set of tools for studying specific biomolecular interactions of importance for understanding physiological function and diseases at the cellular level.